The findings of upper abdominal sonography in three patients with asplenia syndrome are reported. Beside the juxtaposition of the abdominal aorta and inferior vena cava, two additional signs of the asplenia syndrome are discussed: absent splenic vein in pancreatic sonography and midline portal vein. While upper abdominal sonography is not diagnostic in determining the absence or presence of splenic tissue, it seems to be helpful in the identification of upper abdominal vascular anatomy. By demonstrating juxtaposition of the abdominal aorta and inferior vena cava, absent splenic vein, and midline portal vein, upper abdominal sonography can play a significant part in the diagnosis of asplenia syndrome. Alternative diagnostic approaches are discussed.